The prospects for Near Infrared (NIR) spectroscopy and imaging of the breast for detection, characterization,[unreadable] and monitoring of disease continue to appear promising. The technology is particularly attractive in this[unreadable] setting because it offers low-cost, non-ionizing exposures, very high intrinsic contrast for'pathology and[unreadable] images of functional information associated with physiological and compositional tissue changes. During the[unreadable] current funding period Project IV, Near Infrared Spectroscopy and Imaging, has realized an NIR,imaging[unreadable] system that creates quantitative maps of hemoglobin concentration, oxygen saturation, water content and[unreadable] scattering parameters in vivo. The system is clinically operational, collects three-dimensional, multi-spectral[unreadable] optical data and produces two and three-dimensional images of the breast volume of interest. It has been[unreadable] used to deliver well over 100 clinical exams ? data which has been analyzed to (i) establish normative[unreadable] responses in breasts without disease (ii) explore optical property variations with menstrual cycle and[unreadable] changes in breast compression at time of exam, (iii) estimate NIR image contrast in breasts with screening[unreadable] abnormalities, and (iv) correlate NIR imaged parameters with pathological markers identified through[unreadable] histology. The proposal for continuation of Project IV builds on this foundation in several significant ways[unreadable] through a research plan that consists of both technical and clinical advances. Technically, it will extend the[unreadable] spectroscopy and imaging systems available through incorporation of both hardware and software based[unreadable] coregistrations with MR (Magnetic Resonance) and wideband spectral acquisitions through both full-field[unreadable] optical arrays and localized point spectroscopy probes. Clinical involvement will not only include continued[unreadable] NIR imaging of screening abnormalities recommended for biopsy but also extend to larger palpable masses[unreadable] on clinical breast exams and locally advanced breast cancers receiving neoadjuvant therapy, the long-term[unreadable] goal of this research is to determine the likely role of NIR breast imaging for risk assessment, early detection,[unreadable] differential diagnosis, treatment prognosis and therapy monitoring, It is expected that sufficient evidence will[unreadable] be generated during the requested funding period to allow convincing estimates of the potential of NIR[unreadable] breast imaging as an alternative for differential diagnosis, and pilot data in support of a role in treatment[unreadable] prognosis and therapy monitoring which would inform decisions on the initiation of multi-center trials with the[unreadable] technology in the future.